• Title/Summary/Keyword: acoustic emission technology

Search Result 320, Processing Time 0.026 seconds

DETECTING OF SCUFFING USING ACOUSTIC EMISSION

  • Kim, J.H.;Kim, T.W.;Cho, Y.J.
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
    • /
    • 2002.10b
    • /
    • pp.191-192
    • /
    • 2002
  • The scuffing failure is a critical problem in modern machine components, especially for the requirement of high efficiency and small size. In this study. scuffing experiments are conducted using Acoustic Emission(AE) measurement by an indirect sensing approach to detect scuffing failure. Using AE signals we con get and indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surface in real time. The FFT(Fast Fourier Transform)analyses of the AE signal are used to understand the interfacial interaction and the relationship between the AE signal and the state of contact is presented.

  • PDF

Acoustic Emission Characteristics of Plasma Sprayed Ceramic Coating Layer after Salt Spray (플라즈마용사 세라믹코팅 피막부식재의 음향방출 특성)

  • 김귀식;박경석;홍용의
    • Journal of Ocean Engineering and Technology
    • /
    • v.15 no.3
    • /
    • pp.69-74
    • /
    • 2001
  • This paper was to investigate of a adhesiveness for the plasma sprayed coating materials did salt spray by acoustic emission method in tensile loadings. The powders used for the coating were nickel aluminum composite powder Ni-4.5wt.%Al and titanium dioxide powder $TiO_2$. These powders were coated on a carbon steel S45C by plasma spray method. The result solution was a 5% NaCl and the slat spray times were 2, 5 and 10 hours respectively. The salt solution penetrated into the surface of the substrate through pore of the coating layer built in the process of plasma spay. Corrosion productions formed on the surface of substrate. The adhesiveness between the substrate and the coating layer is weaken by corrosion and the exfoliation initiated chiefly at the corrosion surface of the substrate. The AE events and energy of the corroded coating specimens decreased as the salt spray times increased.

  • PDF

A Study on the Fracture Characteristics of CFRP by Acoustic Emission (2) (음향방출법에 의한 탄소섬유강화 플라스틱의 파괴특성에 관한 연구 (2))

  • 윤종희;이장규;박성완;우창기;김봉각;조진호
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2004.04a
    • /
    • pp.58-63
    • /
    • 2004
  • This study is to investigate a fracture characteristics of carbon fiber reinforced plastics (CFRP) under the tensile loading as a function of acoustic emission (AE) according to the frequency analysis (transient mode) and AE source location (location mode). It was found that the fracture mechanism of AE frequency analysis was a useful tool for the estimation of different type of fracture in CFRP, i.e., matrix(epoxy resin) cracking, delamitation and fiber breakage same as AE amplitude distribution.

  • PDF

Residual Stress Measurement by L$_{CR}$ Wave and Acoustic Emission Characteristics from Fatigue Crack Propagation in STS316L Weldment (STS316L용접재의 표면파에 의한 잔류응력 측정과 균열진전시의 음향방출특성)

  • 남기우;박소순;안석환
    • Journal of Ocean Engineering and Technology
    • /
    • v.17 no.1
    • /
    • pp.47-54
    • /
    • 2003
  • In this study, the residual stress and the acoustic emission Charactreistics from fatigue crack propagation were investigated, bused on the welded material of STS316L. The residual stress of welding locations could be evaluated by ultrasonic parameters, such as L$_{CR}$ wave velocity and L$_{CR}$ wave frequency; the residual stress between base metal and weld metal was evaluated. In the fatigue tests, three types of signals were observed, regardless of specimen condition, base metal, and weld metal. Based on NDE analysis of AE signals by the time-frequency analysis method, it should also be possible to evaluate, in real-time, the crack propagation and final fracture process, resulting from various damages and defects in welded structural members.

Leak Detection Technique of Pressure Vessel Using Acoustic Emission Signal (음향방출 신호를 이용한 압력용기의 누설 검사기법 개발)

  • 이성재;정연식;강명창;김정석
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.13 no.4
    • /
    • pp.95-99
    • /
    • 2004
  • In this study, the leak detection technique of pressure vessel by using acoustic emission(AE) signal is suggested experimentally. The leak of pressure vessel is located at the welding line due to welding defects. we measured the AE signal using Rl5I sensor, and examined the AE parameters in leak condition. It is investigated that the mean value of AE signal is dependent on leak source location. So the absolute mean value of AE signal is adopted as dominant AE parameter. We proposed leak detection algorithm using AE signal mean value for monitoring the leak source location.

A Study on the Fracture Characteristics of CFRP by Acoustic Emission (1) (음향방출법에 의한 탄소섬유강화 플라스틱의 파괴 특성에 관한 연구 (1))

  • 윤종희;박성완;이장규;우창기
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.10a
    • /
    • pp.283-288
    • /
    • 2003
  • The object of this study is to investigate a fracture characteristics of static tensile test as a function of acoustic emission according to the fiber orientation $\theta=0^{\circ}C$ in carbon/epoxy composites, CFRP. On tensile loading, it was recognized that the fracture characteristics of CFRP in a unidirectional composites. Using the results of the AE analysis(a=2mm), it was found that the amplitude distributions of AE signals corresponding the matrix cracking, fiber debonding or delamination, and fiber breaking are 55~70dB(<200sec), 100dB(200~600sec), and 80dB(>600sec).

  • PDF

The Evaluation of Mixed Welded SM 490A Steel by Acoustic Emission (3) (음향방출법에 의한 SM 490A 강의 복합용접성 평가 (3))

  • 이장규;인승현;우창기;박성완;김봉각
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.10a
    • /
    • pp.289-294
    • /
    • 2003
  • The object of this study is to investigate the effect of compounded welding by using acoustic emission (AE) signals fur weld heat affected zone (HAZ) in tensile testing. This study was carried out a SM 490A high tension steel for electronic shielded metal are welding (SMAW), $\textrm{CO}_2$ gas arc welding and TIG welding. And correspondingly, the root openings are 3, 4 and 2.8mm. Data displays are based on the measured parameters of the AE signals, along with environmental variables such as time and load. These history plots give us useful and powerful information to analyze the results of material evaluation testing.

  • PDF

A Study on the Damage Estimation of CFRP using Acoustic Emission (음향방출을 이용한 탄소섬유강화 플라스틱의 손상 평가에 관한 연구)

  • 이장규;박성완;김봉각
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.10a
    • /
    • pp.307-312
    • /
    • 2003
  • The object of this study is to investigate a damage estimation of single edge cracked tensile specimens ($2_a$/W) as a function of acoustic emission (AE) according to the unidirectionally oriented carbon/epoxy composites, CFRP AE signals were analyzed and classified 3 regions by event counts, energy and amplitude for coressponding applied load. On tensile loading and using the results of the AE analysis, it was found that the event counts, cumulative counts or energy, and amplitude distributions useful for the prediction of damage failure.

  • PDF

Optimization of Nano-machining parameters using Acoustic Emission and Taguchi Method (음향방출과 다구찌 방법을 이용한 나노머시닝 가공조건의 최적화)

  • 손정무;이성환;최장은
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
    • /
    • 2003.04a
    • /
    • pp.50-55
    • /
    • 2003
  • Atomic force microscope(AFM) techniques are increasingly used for tribological studies of engineering surfaces at scales ranging from atomic and molecular to microscale. AFM with suitable tips is being used for nanofabrication nanomachining purposes. In this paper, machining characteristics of silicon have been investigated by nano indentation and nano scratch. Mechanisms of material removal on the microscale are studied and the Taguchi method is introduced to acquire optimum parameters for nanomachining. This work shows effectiveness of the Taguchi method in nanomachining. Also, Acoustic Emission(AE) is introduced for the monitoring of nanomachining.

  • PDF

Characteristic of Ductile Regime AFM Machining Using Acoustic Emission (AE를 이용한 AFM 연성 영역 가공 특성 연구)

  • Ahn Byoung-Woon;Lee Kwang-Ho;Lee Seoung-Hwan
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.15 no.4
    • /
    • pp.15-21
    • /
    • 2006
  • Recently, atomic force microscope(AFM) with suitable tips is being used for nano fabrication/nanometric machining purposes. In this paper, acoustic emission(AE) was introduced to monitor the nanometric machining of brittle materials(silicon) using AFM. In the experiments, AE responses were sampled, as the tip load was linearly increased(ramped load), to investigate the machining characteristics during a continuous movement. By analyzing the experimental results, it can be concluded that measured AE energy is sensitive to changes in the mechanism of material removal including the ductile-brittle transition during the nanometric machining. The critical depth of cut value for the transition is evaluated and discussed.